Apparatus and method for pneumatically tensioning and supporting tubular fabric on a circular knitting machine



Dec. 29, 1970 H. SHIELDS 3,550,403

APPARATUS AND METHOD FOR PNEUMATICALLY TENSIONING AND SUPPORTING TUBULAR FABRIC ON A CIRCULAR KNITTING MACHINE Filed July 22, 1969 SOURCE Ana INVENTOR.

55 HARPER SHHELbS M flail, dig. M9

ATTORNEYS United States Patent m APPARATUS AND METHOD FOR PNEUMATI- CALLY TENSIONING AND SUPPORTING TUBULAR FABRIC ON A CIRCULAR KNIT- TING MACHINE Harper Shields, Burlington, N.C., assignor to Alamance Industries, Inc., Burlington, N.C., a corporation of North Carolina Filed July 22, 1969, Ser. No. 851,134 Int. Cl. D04b 15/92 US. Cl. 66150 12 Claims ABSTRACT OF THE DISCLOSURE Air currents are directed downwardly in the needle cylinder to pneumatically tension an elongate tubular fabric article blank, such as panty hose blanks, and to draw the article downwardly into the upper end of the vertically disposed portion of a conveying conduit. Air currents are also directed upwardly in the lower portion of the conveying conduit to support and limit the downward movement of the lower end of the article at a predetermined level below the needle cylinder. Since the article is confined in a relatively short space, it is not drawn out to its full length during the knitting operation and it does not become twisted as the needle cylinder rotates.

This invention relates generally to an apparatus and method of pneumatically tensioning and supporting tubular articles as they are knit on circular hosiery knitting machines and more particularly to an improved tensioning and supporting apparatus for use in knitting elongated article blanks, such as panty hose blanks and the like.

Most circular hosiery knitting machines are provided with pneumatic means for drawing air currents downwardly through the needle cylinder to apply downward tension on the hosiery article blank as it is being knit. A hosiery conveying conduit extends downwardly from the needle cylinder and to the floor where it is provided with a right-angle bend or U-shaped turn. The conveying conduit then extends upwardly so that the completed hosiery blank is carried to a conveniently located collection chamber where it may be easily removed by the operator. The bend or turn in the conveying conduit is usually positioned far enough below the knitting point that a hosiery blank of about 30 to 40 inches long may be knit without the lower end extending into the bend or turn.

Because of the current popularity of panty hose and the short skirts and dresses being worn, it has become necesa sary to knit longer hosiery blanks than the take-ups of the machines were designed to handle. If the hosiery blank is of such length that the lower end reaches the bend in the conveying conduit before knitting is completed, the hosiery blank becomes twisted so that it is removed from the machine in a twisted, rope-like configuration which is difiicult to untwist and straighten out and the untwisting frequently causes picks in the hosiery blank.

In an attempt to overcome this twisting problem, many knitting machinery manufacturers now make the legs of the knitting machine longer so that the knitting location is spaced a substantially greater distance above the floor level. Some hosiery manufacturers have also modified existing knitting machines by adding longer legs to the machine and increasing the length of the vertical portion of the conveying conduit. This raises the level of the knitting machine above that to which the knitters and fixers are accustomed. Openings have been cut in the floor beneath the knitting machines in some hosiery mills so that the hosiery blank is drawn straight through the floor. In many cases, hosiery machines are located where it is not practical or possible to cut through the floor.

Patented Dec. 29, 1970 ice With the foregoing in mind, it is an object of the present invention to provide an apparatus and method for pneumatically tensioning and supporting tubular fabric article blanks as they are being knit on circular knitting machines and which may be economically applied to the machines.

In accordance with this invention, air currents are directed downwardly in the needle cylinder and in the upper portion of the conveying conduit to draw the hosiery article downwardly and apply tension thereto. Air currents are also directed upwardly in the lower portion of the conveying conduit to limit the downward movement of the lower end of the hosiery article and maintain it above the level of the bend or turn until completion of the knitting of the hosiery blank.

More specifically, the present apparatus includes a tubular perforated article retaining basket which is supported for rotation with the needle cylinder and inside of the upper portion of the vertical section of the conveying conduit. Valve means is provided for properly directing the air currents through the retaining basket and in timed relationship to operation of the knitting machine. The valve means is operated by conventional pattern means on the knitting machine so that the lower end of the hosiery article is maintained at a level above the bend or turn in the conveying conduit until the knitting is completed. Then, the valve means operates to direct air currents through the conveying conduit and carry the hosiery article into a collection chamber at the end of the conveying conduit.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary vertical sectional view through the needle cylinder of the knitting machine and the inlet end of the article conveying conduit, illustrating the manner in which the pneumatic tensioning and supporting apparatus of the present invention is associated therewith; and

FIG. 2 is a vertical sectional view taken substantially along the line 2-2 in FIG. 1.

Only those portions of a circular hosiery knitting machine are shown which are necessary to an understanding of the operation of the pneumatic tensioning and supporting apparatus of the present invention. The knitting machine includes a needle cylinder 10 which is provided with vertically extending slots or grooves adapted to receive the usual selector jacks 11 and latch needles 12. Sinkers 13 are supported for radial movement in a sinker bed 14 fixed to the upper end of the needle cylinder 10. The sinkers 13 cooperate with the needles 12 in the usual manner to form courses of stitch loops with each rotation of the needle cylinder 10. The cylinder 10 may continuously rotate in one direction to form seamless tubular fabric blanks for use in forming stockings, panty hose, leotards, and the like, and it may also reciprocate at times to form heel and/or toe pockets in. the seamless tubular fabric.

A dial 15 is supported at the upper end of the needle cylinder and in the circle of needles 12 and contains conventional transfer bits or jacks, not shown. In the usual pneumatic take-down system for circular hosiery knitting machines, air currents are drawn inwardly around the dial 15 and are directed downwardly through the needle cylinder 10 to apply downward tension on the knit article to draw it down the needle cylinder 10 and into the upper end of an article conveying conduit. The conduit extends vertically beneath the needle cylinder 10 to a point adjacent the floor where it forms a right-angle bend or turn and its other end is connected to a suitable collection chamher. A vacuum line is connected to the conduit at a point beyond the bend so that the article is drawn downwardly in the vertical portion of the conduit and in a substantially straight condition. If the article is longer than the vertical portion, the lower end passes into the bend and a high degree of twist is imparted to the article.

In accordance with the present invention, the inlet end of an article conveying conduit, broadly indicated at C, is positioned to receive the article as it is drawn down the needle cylinder and its other end is connected to a collection chamber 16. A funnel-shaped fabric guide is supported at its upper end on the upper inner portion of the needle cylinder 10 and its lower end is connected to the upper end of a liner tube 21 which extends downwardly and out of the lower end of the needle cylinder 10. The lower portion of the liner tube 21 is supported for rotation by means of an anti-friction ball bearing 22 which is supported on the inside of a collar 23. The collar 23 is provided with a mounting flange which is fixed on a horizontal portion of the knitting machine frame 24. The collar 23 has a downwardly depending portion which supports the upper end of an enlarged portion 25 of the conveying conduit C. The lower end of the enlarged portion 25 is tapered inwardly as at 26 and is connected to a vertically extending reduced portion 27.

The reduced portion 27 is provided with a substantially right-angle bend 28 which is located closely adjacent the floor beneath the knitting machine. The liner tube 20, the enlarged portion 25 and the reduced portion 27 collectively from a vertically extending portion of the conveying conduit C which extends down below the needle cylinder 10 and to the bend 28. The conveying conduit C extends horizontally and then upwardly where it is connected to a collection bin or chamber 16. An enlarged valve chamber 31 is interposed in the conveying conduit C and between the bend 28 and the collection chamber 30. A one- Way valve 32 is hingedly supported in the valve chamber 31 for movement between the solid and dotted-line positions.

A fabric retaining chamber, in the form of a tubular perforated article retaining basket 35 is supported at its upper end on the lower end of the liner tube 21 and its lower end is open and terminates adjacent the lower end of enlarged portion 25. One end of a vacuum or suction tube 37 is connected to the upper portion of the enlarged portion 25 of the conveying conduit C and its other end is connected to a suitable vacuum source, such as the inlet side of a blower type fan 40 which is driven by an electric motor 41. A cut-off valve 42 is supported in the vacuum tube 37 and is operated by control means, such as a solenoid 43 which is connected to the cut-off valve 42 by suitable linkage. The solenoid 43 is adapted to at times move the cut-off valve 42 from the open position shown to a closed position.

Pattern means is provided for controlling the operation of the cut-olf valve 42 in the proper timed relationship to operation of the machine. To this end, one side of the solenoid 43 is connected to a main electricity supply line 45 by a wire 46 and the opposite side is connected to one side of a switch 47 by a wire 50. The opposite side of the switch 47 is connected to a main electricity supply line 51 by a Wire 52. The switch 47 is operated at predetermined intervals by a suitable cam, not shown, on a pattern drum 54, in a manner to be presently described.

An air jet nozzle 55 is supported in the horizontal portion of the conveying conduit C and provides means for directing air currents toward the collection chamber 16 to move the completed articles through the conduit and into the collection chamber. One end of an air pressure line 56 is connected to the air jet nozzle 55 and its other end is connected to a suitable source of air under pressure, as schematically illustrated at 57. A valve 60 is interposed in the air pressure line 56 and is operated by control means, such as a solenoid 61. Pattern means is also provided for controlling the operation of the valve 60 in the proper timed relationship to operation of the machine. To this end, one side of the solenoid 61 is connected to the main line 45 and the other side is connected to one side of a switch 62 by a wire 63. The other side of the switch 62 is connected to the main line 51 by a wire 64. The switch 62 is operated at predetermined intervals by means of a suitable cam, not shown, on the main pattern drum 54.

Inlet valve means is interposed in the conveying conduit C and between the bend 28 and the collection chamber 16 to at times permit air currents to enter the conveying conduit and to be drawn upwardly into the lower end of the basket 35 and into the tube 37. The inlet valve means includes a branch pipe which is closed at its outer end and its inner end is connected to the conveying conduit C at its other end. Suitable air entrance openings 72 are provided in the branch pipe 70 and are normally closed by a curved cover plate 73 which straddles the branch pipe 70. Control means, in the form of a solenoid 74, is provided for controlling the operation of the inlet valve means. Pattern means is provided for operating the solenoid 74 and includes a wire 75 which is connected at one end to the solenoid 74 and its other end is connected to the main line 45. The other side of the solenoid 74- is connected to one side of a switch 76 by a wire 77 and the other side of the switch 76 is connected to the main line 51. A cam 80 on the pattern drum 54 controls the operation of the switch 76, in a manner to be presently described.

METHOD OF OPERATION As is well known, most hosiery articles, such as panty hose blanks, are started by knitting a make-up at the leading end and, if desired, an inturned welt may be formed in the usual manner by the use of the transfer jacks in the dial 15. During the formation of the make-up and welt of the panty hose blank, indicated at P, the motor 41 operates to impart rotation to the fan type blower 40 and thereby draw air downwardly through the vacuum tube 37, the valve 42 being in the open position shown. The one-way valve 32 and the inlet valve cover 73 are each closed, as shown in FIG. 1, so that air is drawn downwardly around the dial 15 and air currents are directed downwardly through the liner tube 21 and into the vacuum tube 37. Thus, the air currents moving down the upper portion of the vertical portion of the conveying conduit apply substantially uniform downward tension on the fabric as it is being knit.

Since the liner tube 21 and the basket 35 are rotating at the same speed as the knit blank P and the needle cylinder 10, there is no tendency for the blank to twist as it is drawn down into the basket 35. When the machine has knit a sufficient number of courses that the lower or leading end of the blank P reaches substantially the lower end of the perforated basket 35, the pattern drum 54 will have rotated a sufiicient amount that the cam 80 will close the switch 76 to activate the solenoid 74 and raise the curved cover plate 73 so that the openings 72 are uncovered. With the openings 72 uncovered, air is also drawn inwardly through the branch pipe 70 and air currents are directed upwardly through the lower portion of the vertical portion of the conveying conduit C, through the perforated basket 35 and into the vacuum tube 37. These currents of air moving upwardly through and around the bottom of the perforated basket 35 prevent the lower end of the tubular blank from moving out of the lower open end of the basket 35 so that with continued knitting, the blank will fold upon itself and become bunched up in the perforated basket 35. Thus, the lower end of the blank is supported and maintained above the right-angle bend 28 in the conveying conduit 27 so that the blank will accumulate above and on the bunch and will not be twisted during the knitting operation.

Upon completion of the knitting of the desired length of blank, the final end or upper end of the blank is castoff and released from the needles, in the usual manner. At this time, a cam on the pattern drum 54 will close the switch 47 and actuate the solenoid 43 to thereby close the valve 42 and cut off the vacuum in the tube 37. The cam 80 will also permit the switch 76 to open and the openings 72 will be closed by the cover plate 73 to close the inlet valve means.

The blank P then falls down through the perforated basket 35 and into the bend 28 in the conveying conduit C. After the blank P reaches the lower end of the vertical portion of the conveying conduit C, a cam on the pattern drum 54 causes the switch 62 to close to open the valve 60 so that air under pressure enters the line 56 and is discharged through the air jet nozzle 55. This directs air currents toward the collection chamber 16- and moves the blank P along the conveying conduit C, opening the oneway valve 32, as the blank is moved to and deposited in the collection chamber 16, where it can be easily removed by the operator for inspection. Before beginning the knitting of the next stocking blank, the pattern drum 54 will move to position a cam to close the switch 47 so that the valve 42 will open and vacuum will be drawn in through the tube 37. Also, the switch 62 is opened to close the valve 60 and cut off the air under pressure entering through the air jet nozzle 55. The cover plate 73 will move down to close the air openings 72, until the lower end of the blank has reached the lower end of the basket 35.

Thus, the machine is then ready to knit another tubular blank. The air currents are initially directed downwardly on the tubular blank until the lower end reaches the lower portion of the perforated basket 35, at which time air currents will also be directed upwardly to prevent further downward movement of the leading or lower end of the tubular blank. The upwardly directed air currents prevent the lower end of the blank from moving down into the bend 28 in the conveying conduit C to thereby prevent twisting of the blank as it is supported and maintained at a predetermined level in the conveying system.

In the drawings and specification there has been set forth a preferred embodiment of the invention and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

I claim:

1. An apparatus for pneumatically tensioning and supporting an elongate tubular fabric article as the article is being knit on a circular knitting machine having a rotating hollow needle cylinder through which the article passes as it is knit, a collection chamber spaced from said needle cylinder, and an article conveying conduit having one end positioned to receive the article from said needle cylinder and the other end being connected to said collection chamber, said conveying conduit having a portion extending substantially vertically below said needle cylinder and including a bend at the lower end, said apparatus comprising i (a) means for directing air currents downwardly in said needle cylinder and in the upper portion of the vertical portion of said conveying conduit to draw the article downwardly and apply tension thereto, and

(b) means for directing air currents upwardly in the lower portion of the vertical portion of said conveying conduit and out of an intermediate portion thereof to limit the downward movement of the lower end of the article to a location spaced above the bend in said conveying conduit and to maintain the lower end of the article at said location so that with continued knitting the article will become bunched at said location and accumulate upwardly thereon.

2. An apparatus according to claim 1 wherein said bend is at substantially a right-angle and including (0) means for terminating the direction of the upward and downward air currents upon completion of the knitting of the article to release the article to permit the same to fall down the vertical portion of said conveying conduit, and

(d) means for directing air currents along said conveying conduit and toward said collection chamber to move the article through said conveying conduit and into said collection chamber.

3. An apparatus according to claim 2 wherein said means (a) comprises a vacuum source and a tube connected at one end to said vacuum source and at the other end to the upper portion of said vertical portion of said conveying conduit.

4. An apparatus according to claim 3 wherein said means (b) comprises inlet valve means interposed in said conveying conduit between said right-angle bend and said collection chamber, and means for operating said inlet valve means to at times permit air currents to enter said conveying conduit and be drawn upwardly in said vertical portion of said conveying conduit and into said tube.

5. An apparatus according to claim 3 including a tubular perforated article retaining basket positioned within said vertical portion of said conveying conduit and adjacent the point of connection of said tube with said conveying conduit, said perforated basket having an open lower end, and means supporting the upper end of said basket for rotation with said needle cylinder.

6. An apparatus according to claim 5 wherein said support means for said basket comprises a liner tube communicatively connected at its lower end to the upper end of said basket, said liner tube extending upwardly inside of said hollow needle cylinder and having an upper inlet end drivingly connected with said needle cylinder, the lower portion of said liner tube extending downwardly below said needle cylinder, and bearing means supporting the lower portion of said liner tube and being supported on said knitting machine so that said basket moves with said needle cylinder.

7. An apparatus according to claim 3 wherein said means (c) comprises cut-off valve means interposed in said tube and between said vacuum source and said conveying conduit, and means for selectively operating said cut-otf valve and being operable to position said cut-off valve to permit air currents to be drawn inwardly through said tube and to position said valve to terminate the movement of air currents into said tube.

8. An apparatus according to claim 3, wherein said means (d) comprises an air jet nozzle interposed in said conveying conduit and between said right'angle bend and said collection chamber, and valve means for selectively admitting air under pressure to said air jet nozzle for causing air currents to flow from the inlet end of said liner tube and to said collection chamber to thereby move the article through said conveying conduit and into said collection chamber.

9. An apparatus according to claim 8 wherein said knitting machine includes pattern means operated in timed relationship to operation of said machine, and including first control means operable by said pattern means for controlling the operation of said cut-off valve, second control means operable by said pattern means for controlling said valve means for said air jet nozzle, and third control means operable by said pattern means for controlling the operation of said inlet valve means.

10. An apparatus according to claim 4 including oneway valve means interposed in said conveying conduit between said inlet valve means and said collection chamber to permit the movement of air currents and knit articles toward said collection chamber and to prevent movement of air currents in the opposite direction.

11. A method of pneumatically tensioning and supporting an elongate tubular fabric article as the article is being knit on a circular knitting machine having a rotating hollow needle cylinder through which the article passes as it is knit, a collection chamber spaced from said 7 needle cylinder, and an article conveying conduit having one end positioned to receive the article from said needle cylinder and the other end being connected to said collection chamber, said conveying conduit having a portion extending substantially vertically below said needle cylinder and including a substantially right-angle bend at the lower end; said method comprising the steps of (a) directing air currents downwardly in said needle cylinder and in the upper portion of the vertical portion of said conveying conduit to draw the article downwardly and apply tension thereto; and (b) directing air currents upwardly in the lower portion of the vertical portion of said conveying conduit and out of an intermediate portion thereof to limit the downward movement of the lower end of the article to a location spaced above the right-angle bend in said conveying conduit and to maintain the lower end of the article at said location so that with continued knitting the article will become bunched at said location and accumulate upwardly thereon. 12. A method according to claim 11 including the additional steps of (c) terminating the direction of the upward and downward air currents upon completion of the knitting of References Cited UNITED STATES PATENTS Booton et al 66149 Luchi 66149 Tenconi 66-149 Moretta 66-149 Mahler 66149 Thore 66-149 FOREIGN PATENTS Great Britain.

WM. CARTER REYNOLDS, Primary Examiner US. Cl. X.R. 

